1. Field of the Invention
The present invention relates to a digital image processing device, and more particularly, to a digital image processing device and a method for forming natural edge shapes for enlarged images and simultaneously emphasizing edge brightness contrast.
2. Description of the Related Art
In order to enlarge an original digital image into a larger digital image, the relationship between each position of the original digital image and each position of the enlarged digital image are calculated, and a pixel value of each position of the enlarged image is calculated in terms of pixels adjacent to each position of the enlarged image and each position of the mapped original image. If an original image pixel at each mapped position exists, a value of the pixel can be obtained, but, if the original image pixel does not exist, a new pixel value has to be calculated in terms of the adjacent pixels.
A convolution method exists for calculating new pixel values, wherein an added value of pixels adjacent to a target pixel to a position of the target pixel are allocated, and the added values are constructed in an arrangement called convolution kernel or masking. However, the convolution method has a problem of blurring edges when enlarging images at a high enlargement factor.
In order to reduce the problem, unsharp masking is performed to emphasize the blurred edges. Specifically, the blurred portions of the original image are removed to improve image sharpness. However, when the unsharp masking is performed, the stair-stepping artifact which occurs on the edges of an enlarged image is emphasized, which results in jagged edges.